as long as she is of age before the yuri starts i will be ok with it
Having a relationship with your guardian is so messed up tho
it can be seen from that perspective however if she is her parental figure until she is legal and then they start a relationship i have no problem with that
if you really think about it though who is who's guardian in this manga though the adult or the teenager ? seeing as how normally a guardian would know simple things like cooking lol just saying
Hopefully, it'll be a relationship strictly platonic with no yuri involved between them